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At a loss... Solved?

Discussion in 'XJ Technical Chat' started by aaron_acrusto, Jul 21, 2012.

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  1. aaron_acrusto

    aaron_acrusto Member

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    I don't know where to go next. I just can't get this thing to get running.
    So far I have:
    Put the valves in spec
    Cleaned carbs, pulled every jet, sprayed air through everything.
    Pulled the pms screws, and enrichment circuits. Sprayed air and cleaner through both.
    Set pms screws to 2.5 out from bottom
    Set floats
    Bench sync
    New plugs.

    I have no change. The bike fires right up, so I'm assuming it's getting fuel. I've gotten it to hold an idle with the choke at about halfway, but if I close it, it dies. Or if I can get it hold idle, it dies with throttle. I've tried adjusting the mixture screws in 1/4 turn intervals, to no avail. New plugs are mostly white, with a faint touch of brown.

    I don't know what to do. Help before I pull out all my hair!
     
    aaron_acrusto, Jul 21, 2012
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  2. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    Also, I noticed my old set of carbs had 205 air jets. I'm assuming this was to compensate for the aftermarket exhaust. I swapped out my 195s for the 205s with no change.
     
    aaron_acrusto, Jul 21, 2012
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  3. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    I just ran a compression test. 80 psi across all 4 cylinders....
     
    aaron_acrusto, Jul 21, 2012
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  4. kardoktor

    kardoktor New Member

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    Re: At a loss...

    Still seems like you're not getting adequate fuel...have u verified good supply from the tank thru the petcock? verify the vacuum line to your diaphragm on the petcock is not leaking vacuum and/or try running it with the petcock in the "prime" position. or simply use an alternate fuel source like another fuel container to gravity feed your carbs. Also how did u go about setting the float levels? Once oyuve determined good fuel supply, we can start progressing step by step.
     
    kardoktor, Jul 21, 2012
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  5. mtnbikecrazy55

    mtnbikecrazy55 Active Member

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    Re: At a loss...

    Uh oh, 80 ain't lookin good :(
     
    mtnbikecrazy55, Jul 21, 2012
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  6. smurf667

    smurf667 Member

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    Re: At a loss...

    80 psi is very low, and it's running too lean too.
     
    smurf667, Jul 21, 2012
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  7. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    I wets set the floats to 3 mm from the flange on the carb body. I had a crack in the vacuum line at the very end where it attaches to the petcock. I cut that part off and refitted it. I have also tried running on prime. Fuel is flowing freely through the bowls when I release the drain screw, so I'm pretty sure I have fuel flow.

    I have tried running it with up to 4 turns out on the pilot screw, and still no change on the plugs. Or on the throttle for that matter
     
    aaron_acrusto, Jul 21, 2012
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  8. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    I have also flooded the entire carb area with propane, to test for vacuum leak, everything seems ok on that front.
     
    aaron_acrusto, Jul 21, 2012
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  9. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    Would the low compression cause the diaphragms to not pull enough vacuum to get it running off idle?
     
    aaron_acrusto, Jul 21, 2012
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  10. wizard

    wizard Active Member

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    Re: At a loss...

    Have you tested the comp' with a spoon of oil in the bores ?
    80 psi is well low but they are even, I would try a different gauge.
    Couple of silly things to check, are the 2 jets reversed ? throttle cable switched with the enrichment cable, throttle cable getting hooked on the manifold clamps, all these things have been done before.
     
    wizard, Jul 21, 2012
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  11. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    Cables are correct and not snaggIng. On the top end, the 205 is furthest from the cover screw hole, then a 50. On the bottom end the 110 is screwed into the emulsion tube, with a 40 in the shorter tube behind it.

    Oil brought up to around 100 psi
     
    aaron_acrusto, Jul 21, 2012
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  12. adrian1

    adrian1 Active Member

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    Re: At a loss...

    What's the history of this bike? Have you just bought it or has the current running condition been around for a while in your possession?
     
    adrian1, Jul 21, 2012
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  13. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    Bought it about 4 years ago. It ran when I bought it, never really had it on the road. I moved that summer I bought it, put sta bio in the tank, ran it
    Then drained it. A year later I picked it up. I started trying to work on, not very seriously though. Then I lost the keys, and couldn't get the drain screws unstuck. So it has been sitting with bad gas through two winters under a tarp.

    This year I've finally started attacking it. I went to clean the carbs, and broke a float pillar. I bought new carbs, came home, put them on the bike, pressed the button, and it started up beautifully. Took a break to wrap my head around what it needed next, and came back to it a month later. Replaced the solenoid, and fusebox because of some ignition issues. Then I took on the valves.

    After I shimmed the valves, I took the carbs off. I gave them a quick once over, wet set the floats, and put them back on.

    The problem either started after the valve shimming, or the first carb "clean"
     
    aaron_acrusto, Jul 21, 2012
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  14. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    I've also noticed the petcock is pissing fuel out of its center.
     
    aaron_acrusto, Jul 21, 2012
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  15. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Re: At a loss...

    Unles your gauge has a large hose, - - you did it wrong, you need throttle open, plugs out, battery boosted, ignition de-activated.

    This is to spin the motor up for the test.

    Please re-do the test dry - - re-submit your results.
     
    TIMEtoRIDE, Jul 21, 2012
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  16. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    Had all the plugs out and boots grounded to the frame. I didnt open up the throttle.
    By "battery boosted" do you mean hooked up to a charger, or fully charged?
     
    aaron_acrusto, Jul 21, 2012
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  17. wizard

    wizard Active Member

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    Re: At a loss...

    'Boosted' hooked up to a car battery with jump leads.
    (car / truck not running)
     
    wizard, Jul 21, 2012
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  18. adrian1

    adrian1 Active Member

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    Re: At a loss...

    ?? So you're not getting a proper flow to the carbs then?

    You may have already read this but Chacal's comments re cleaning jets is worth repeating:



    http://www.xjbikes.com/Forums/viewtopic/t=8918.html
     
    adrian1, Jul 22, 2012
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  19. aaron_acrusto

    aaron_acrusto Member

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    Re: At a loss...

    I've already done all that. Probed passages with a guitar string, and sprayed cleaner and air through everything.

    The bike starts with the choke. So I don't think that's the problem.
     
    aaron_acrusto, Jul 22, 2012
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  20. TIMEtoRIDE

    TIMEtoRIDE Active Member

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    Re: At a loss...

    That one is worth alot

    When you do the "wet test", use the same amount of oil, 12CC's
    The combustion chambers are 23 CC's

    The volume in the hose for the gauge factors in also.
     
    TIMEtoRIDE, Jul 22, 2012
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